@Carl Love Thanks you,by the way i want Q versus B. 

@ThU Thanks you. 

@Mariusz Iwaniuk Thanks.

@tomleslie Thanks,at first i considered lambda[1]=1.7 and lambda[2]=3.8. Now i want to find all of the roots of the lambda.

@tomleslie Thanks.

@John_Dirichlet Thanks. i want all all of the roots between lambda=0..10